Blood Pressure Variability and Ambulatory Arterial Stiffness Index in Predicting Major Adverse Cardiovascular Events.

Abstract

Background: Increased blood pressure variability (BPV) and ambulatory arterial stiffness index (AASI) are associated with major adverse cardiovascular events (MACE), including stroke, transient ischaemic attack, acute coronary syndrome and cardiovascular (CV) death. However, the prognostic value of AASI and BPV in the same population has not been previously investigated. Aim: To assess the relationship between BPV, AASI and MACE. Methods: This was an ambidirectional observational cohort study. BPV and AASI were measured from 24-Hr ambulatory blood pressure monitor (ABPM). Other indices included standard deviation (SD) of systolic (SBP) and diastolic (DBP) blood pressure and nocturnal dipping status. Statistical analyses included chi-square and Fisher’s exact tests for categorical data. Independent sample t-tests and Mann-Whitney U tests were used for parametric and non-parametric continuous data. Univariate and multivariate logistic regression with odds ratios (OR) and 95% confidence intervals (CI) were used to assess the relationship between BPV, AASI and MACE. Multivariate Cox regression analysis with hazard ratio (HR) and (95% CI) and Kaplan-Meier analyses were conducted for time-to-event (MACE) data. Results: A total of 829 patients (424 males, 405 females) were followed for 4.35 (±1.32) years. There were 38 MACE (4.58%) events. AASI values were significantly greater in patients with MACE compared to those without [0.54 (±0.16) vs 0.45 (±0.16); p < 0.001]. AASI was associated with MACE in univariate analysis (OR: 26.96, 95%CI: 3.77–195.58, p < 0.001), but not in multivariate analysis. SD 24-Hr SBP was a univariate and independent predictor of MACE (adjusted OR: 1.21, 95% CI: 1.07–1.37, p = 0.002). Multivariate Cox regression confirmed this association (HR: 1.07, 95%CI: 1.01–1.14, p = 0.024). Kaplan-Meier analysis showed significantly lower survival in patients with AASI >0.47 (median, p = 0.002). Conclusion: SD 24-Hr SBP was an independent predictor for MACE, while AASI was a potential risk factor.